Automatic snap buckle

ABSTRACT

The subject matter of the solution is an automatic snap buckle intended in particular for joining together sections of safety harness tapes wherein the snap buckle consists of a body and a plug, wherein in the body there is a connection eyelet for sewing of the end of a textile strap of the safety harness, wherein in the plug there is a second connection eyelet for the sewing of the other tape end and wherein the finger of the plug is pushed to a stop, which is a central post located at the end of the slot in the body

The subject of the invention is an automatic snap buckle, intended in particular for joining together sections of safety harness tapes. Employees working at heights must be equipped with individual personal protective equipment to protect them against falling from a height. The basic personal equipment is safety harness, i.e. appropriately sewn together sections of textile tapes, which, when put on the body, are joined together with buckles. The most convenient for an employee are automatic snap buckles, i.e. those whose parts are fastened together under the influence of pressure on both components of the buckle, thus connecting the textile tapes. Such buckles must be secured against accidental disconnection.

Known automatic snap buckles are shown at www.austrialpin.at website where they are described as “Cobra”. These buckles consist of a body with a flat slot for a flat plug finger, being the second component of the buckle. Both, in the body and in the plug there are connection eyelets, through which textile tapes are threaded and sewn in these eyelets.

The body has a system of two ratchets with blades that are designed to snap onto the transverse teeth at the tip of a finger. The rachets are mounted on axes perpendicular to the direction of insertion of the finger into the slot and have external wings on the other side of the axis of rotation for unlocking the rachets. The rachets clamp with the blades on the edge of the finger in bends at the finger teeth and are pressed on the edge by the force of pressure springs embedded in the body. The body has a central post for the central recess in the forehead of the finger, positioning the finger in the slot.

Clamping the buckle involves inserting the finger into the slot in the body until the central recess in the forehead of the finger with the central post closes—during the movement, the blades of the ratchets slide over the finger's teeth, in the final stage they jump over the teeth and clamp in bends at the edges of the finger—the ratchets engage the teeth automatically when the finger is fully inserted. To unfasten the buckle, it should be pressed simultaneously on the outer wings of the ratchets and make the ratchet's blades spread apart so that the toothed finger can be pulled out of the slot. Such buckles usually work properly, the fastening is sure, because to disconnect it you have to press on both wings at the same time, pressing on one of the wings does not open the buckle. However, sometimes, when large forces appear in the security system, e.g. when an employee falls from a height and hooks one wing on a protrusion, the buckle may open unilaterally and then completely unfasten.

According to the invention snap buckle is constructed so that each of the rachets has a cutout on the edge line between the rachet's blade and the axis of rotation. This cutout is shaped according to the tooth shape of the plug finger.

The buckle according to the invention also provides a secure connection with the harness tapes, but provides a two-stage system of securing the buckle against accidental unfastening, which will be described in more detail later in the description.

The subject of the invention is shown in the embodiment in the drawing, in which FIG. 1 shows a cross-section through a slot in the body with a finger inserted as far as it will go, and FIG. 2 —with the finger locked on the second security stage which is with teeth in the cutout in rachets.

As shown in FIG. 1 and FIG. 2 , the snap buckle consists of a body 1 and a plug 2. In the body 1 there is a connection eyelet 3 for the sewing of the end of the textile strap of the safety harness, and in the plug 2 there is a second connection eyelet 4 for the sewing of the other tape end. In FIG. 1 , the buckle is shown in its fully closed state when the buckle parts and thus the harness tapes are connected. The finger 5 of the plug 2 is pushed to the stop, which is the central post 13, located at the end of the slot in the body 1. The finger 5 rests against the central post 13 with the central recess 14 in the forehead of the finger 5, so that the finger 2 cannot slide in the slot from side to side.

In the body 1 there is a system of two rachets 8 with blades 7, which are designed to snap on the bends with the transverse teeth 6 at the end of the finger 5. The rachets 8 are rotatably mounted on the axes 10 perpendicular to the direction of insertion of the finger 5 into the slot and have on the other side of the axis 10 of rotation, outer wings 15 for unlocking the rachets. The rachets 8 clamp with the blades 7 on the edge of the finger 5 in bends at the teeth 6 of the finger and are pressed against the edge of the finger by the force of pressure springs 11 embedded in the body 1. In this embodiment, the wire pressure spring 11 is seated on the pins 12 connecting the halves of the body 1.

The halves of the body 1 are also connected with each other by the central post 13 and on rotation axis 10 of the rachets 8. Clamping the buckle involves inserting the finger 5 of the plug 2 into the slot in the body 1 until the middle recess 14 in the finger forehead contacts the central post 13—during the movement blades 7 of the rachets 8 slide over the teeth 6 of the finger 5, in the final stage they jump over the teeth 6 and clamp in bends on the edges of the finger 5—the rachets 8 latch on the teeth 6 automatically after inserting the finger 5 to the stop. The central recess 14 rests against the central post 13, which protects the finger 5 against lateral movements in the slot, and thus against one-sided, accidental disengagement (unfastening) of any of the rachets 8 under normal operating conditions. To unfasten the buckle, it is needed to simultaneously press on the outer wings 15 of the rachets 8 and make the blades 7 part apart so that the teeth 6 of the finger 5 can be pulled out of the slot.

FIG. 2 shows the buckle in a partially fastened position, when the finger 5 is not pressed all the way in or when one of the wings 15 is accidentally pressed very hard and one of the teeth 6 jumps out of the blade 7 of the rachet 8. The tooth 6 will then jump into the recess 9 at the side edge of finger 5 and the buckle will still be locked, it will be in the connected state. But it may also happen that the second tooth 6 also jumps out of the blade 7 of the second rachet 8, then the buckle will also remain in the locked state, because the second tooth 6 will jump into the recess 9 in the second rachet 8. To release the buckle from this state, it is also necessary to simultaneously press the wings 15 of the rachets 8. 

I claim:
 1. An automatic snap buckle comprising a body with a flat slot for a flat plug finger of a plug which is a second component of the buckle, wherein the body and the plug have connection eyelets for sewing ends of textile tapes connected in them, wherein the body has a system of two ratchets for latching on a transverse finger teeth, which are mounted on axes perpendicular to direction of insertion of the finger into the slot and have external wings for unlocking the rachets, clamped below the teeth on an edge of the finger by a force of pressure springs, wherein in the body there is a central post for a central recess in a finger forehead, characterized by that each of the ratchets (8) has a cutout (9) on an edge line between a blade (7) of the rachet (8) and an axis of rotation (10), and wherein an cutout (9) is shaped according to a shape of a tooth (6) of the plug (2) finger (5). 